Casting project update: 12 Ton Medium Tank

Here is a size comparision showing my '12 ton medium' tank model against Coppestone Castings' Vickers Mk II, upon which it is loosely based. The idea is, this tank model will share two turret variations with another model, both of which can be seen in my previous posts. For the pupose of this image, I balanced the running board on the track assembly, so its sitting rather low. It should be about 2mm higher up. Currently I'm working on the rear hull plate and trying to decide how to do the exhaust pipe which is meant to hang on the back. The question is, whether or not to add it to the hull or have it as a seperate element. If its stuck on the hull, it might prevent the finished casting from leaving the mold.